﻿#include <linux/delay.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/fcntl.h>
#include <linux/fs.h>
#include <linux/gfp.h>
#include <linux/gpio/consumer.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kernel.h>	
#include <linux/kmod.h>
#include <linux/major.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of_gpio.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/poll.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/stat.h>
#include <linux/timer.h>
#include <linux/tty.h>

#include "asm-generic/gpio.h"
#include "asm/uaccess.h"
#include "linux/jiffies.h"
#include "linux/types.h"
#include "linux/wait.h"

#define DRV_FILE "harry_irda"
#define CHR_DEV_NAME "harry_irda"

struct gpio_desc
{
	int gpio;
	int irq;
	char name[128];
	int key;
	struct timer_list timer;
};
static char kern_buf[4];
static struct gpio_desc *gpios;
static int count;

/* 主设备号 */
static int major = 0;
static struct class *gpio_class;
static u64 g_irda_irq_time[68];
static int g_irda_irq_cnt = 0;

/* 环形缓冲区 */
#define BUF_LEN 128
static int g_datas[BUF_LEN];
static int r, w;

struct fasync_struct *button_fasync;

#define NEXT_POS(x) ((x + 1) % BUF_LEN)

static int is_data_buf_empty(void) { return (r == w); }

static int is_data_buf_full(void) { return (r == NEXT_POS(w)); }

static void put_data(char data)
{
	if (!is_data_buf_full())
	{
		g_datas[w] = data;
		w = NEXT_POS(w);
	}
}

static char get_data(void)
{
	char data = 0;
	if (!is_data_buf_empty())
	{
		data = g_datas[r];
		r = NEXT_POS(r);
	}
	return data;
}

static DECLARE_WAIT_QUEUE_HEAD(gpio_wait);

// static void key_timer_expire(struct timer_list *t)
static void key_timer_expire(unsigned long data)
{
	// struct gpio_desc *gpio_desc = (struct gpio_desc *)data;
	put_data(-1);
	put_data(-1);
	g_irda_irq_cnt = 0;
	wake_up_interruptible(&gpio_wait);
	kill_fasync(&button_fasync, SIGIO, POLL_IN);
}
static int parse_irda_data_success(char *buf, int len)
{
	/*parsing data: the pulse low or high depend on irq time*/
	int byte_count, bit_count;
	char byte = 0;
	u64 time;
	/* judge the start conditions*/
	time = g_irda_irq_time[1] - g_irda_irq_time[0];
	if (time < 8000000 || time > 10000000)
	{
		return 0;
	}
	time = g_irda_irq_time[2] - g_irda_irq_time[1];
	if (time < 4000000 || time > 5000000)
	{
		return 0;
	}
	for (byte_count = 0; byte_count < len; byte_count++)
	{
		for (bit_count = 0; bit_count < 8; bit_count++)
		{
			int n = 8 * byte_count + bit_count + 1;
			if ((g_irda_irq_time[4 + 2 * n] - g_irda_irq_time[3 + 2 * n]) > 1 * 1000000)
				byte |= (1 << bit_count);
		}
		buf[byte_count] = byte;
		byte = 0;
	}
	return 1;
}
static int is_repeat_code(char *buf, int len)
{
	u64 time;
	/* judge the start conditions*/
	time = g_irda_irq_time[1] - g_irda_irq_time[0];
	if (time < 8000000 || time > 10000000)
	{
		return 0;
	}
	time = g_irda_irq_time[2] - g_irda_irq_time[1];
	if (time < 2000000 || time > 3000000)
	{
		return 0;
	}

	return 1;
}

static irqreturn_t irda_isr(int irq, void *dev_id)
{
	int ret;
	struct gpio_desc *gpio_desc = dev_id;
	g_irda_irq_time[g_irda_irq_cnt] = ktime_get_ns();
	g_irda_irq_cnt++;
	/*judge the irda start*/

	if (g_irda_irq_cnt == 68)
	{
		ret = parse_irda_data_success(kern_buf, 4);
		if (ret && (kern_buf[0] == (~kern_buf[1])) && (kern_buf[2] == (~kern_buf[3])))
		{
			put_data(kern_buf[0]);
			put_data(kern_buf[2]);
			g_irda_irq_cnt = 0;
			del_timer(&gpio_desc->timer);
			wake_up_interruptible(&gpio_wait);
			kill_fasync(&button_fasync, SIGIO, POLL_IN);
		}
		else
		{
			put_data(-1);
			put_data(-1);
			g_irda_irq_cnt = 0;
			del_timer(&gpio_desc->timer);
			wake_up_interruptible(&gpio_wait);
			printk("get data err: %s", gpio_desc->name);
		}
	}
	else if (g_irda_irq_cnt == 4)
	{
		if (is_repeat_code(kern_buf, 4))
		{
			put_data(kern_buf[0]);
			put_data(kern_buf[2]);
			g_irda_irq_cnt = 0;
			del_timer(&gpio_desc->timer);
			wake_up_interruptible(&gpio_wait);
			kill_fasync(&button_fasync, SIGIO, POLL_IN);
		}
	}
	else
		mod_timer(&gpio_desc->timer, msecs_to_jiffies(100));
	return IRQ_HANDLED;
}

/* */
static ssize_t irda_read(struct file *file, char __user *buf, size_t size,
						 loff_t *offset)
{
	int err;
	char kern_data[2];
	if (size != 2)
		return -EINVAL;
	wait_event_interruptible(gpio_wait, !is_data_buf_empty());
	kern_data[0] = get_data();
	kern_data[1] = get_data();
	if (kern_data[0] == -1)
		return -EIO;
	err = copy_to_user(buf, kern_data, 2); /* copy 2 bytes*/
	return 2;
}
/* 定义自己的file_operations结构体 */
static struct file_operations gpio_key_drv = {
	.owner = THIS_MODULE,
	.read = irda_read,
};

/* 在入口函数 */
static int gpio_drv_probe(struct platform_device *pdev)
{
	int err = 0;
	int i;
	struct device_node *np = pdev->dev.of_node;
	struct resource *res;

	printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__);

	/* 从platfrom_device获得硬件信息（1 设备树；2 .c文件）*/

	if (np)
	{
		/* pdev来自设备树 : 示例
		reg_usb_ltemodule: regulator@1 {
			compatible = "100ask,gpiodemo";
			gpios = <&gpio5 5 GPIO_ACTIVE_HIGH>, <&gpio5 3 GPIO_ACTIVE_HIGH>;
		};
		*/
		count = of_gpio_count(np);
		if (!count)
			return -EINVAL;

		gpios = kmalloc(count * sizeof(struct gpio_desc), GFP_KERNEL);
		for (i = 0; i < count; i++)
		{
			gpios[i].gpio = of_get_gpio(np, i);
			sprintf(gpios[i].name, "%s_pin_%d", np->name, i);
		}
	}
	else
	{
		/* pdev来自c文件
		static struct resource omap16xx_gpio3_resources[] = {
			{
					.start  = 115,
					.end    = 115,
					.flags  = IORESOURCE_IRQ,
			},
			{
					.start  = 118,
					.end    = 118,
					.flags  = IORESOURCE_IRQ,
			},		};
		*/
		count = 0;
		while (1)
		{
			res = platform_get_resource(pdev, IORESOURCE_IRQ, count);
			if (res)
			{
				count++;
			}
			else
			{
				break;
			}
		}

		if (!count)
			return -EINVAL;

		gpios = kmalloc(count * sizeof(struct gpio_desc), GFP_KERNEL);
		for (i = 0; i < count; i++)
		{
			res = platform_get_resource(pdev, IORESOURCE_IRQ, i);
			gpios[i].gpio = res->start;
			sprintf(gpios[i].name, "%s_pin_%d", pdev->name, i);
		}
	}

	for (i = 0; i < count; i++)
	{
		gpio_request(gpios[i].gpio, gpios[i].name);
		gpio_direction_input(gpios[i].gpio);
		setup_timer(&gpios[i].timer, key_timer_expire, (unsigned long)&gpios[i]);
		gpios[i].irq = gpio_to_irq(gpios[0].gpio);
		err = request_irq(gpios[0].irq, irda_isr,
						  IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING, gpios[i].name,
						  &gpios[i]);
	}

	/* 注册file_operations */
	major = register_chrdev(0, CHR_DEV_NAME, &gpio_key_drv); /* /dev/gpio_desc */
	gpio_class = class_create(THIS_MODULE, "harry_irda_class");
	if (IS_ERR(gpio_class))
	{
		printk("%s %s line %d\n", DRV_FILE, __FUNCTION__, __LINE__);
		unregister_chrdev(major, CHR_DEV_NAME);
		return PTR_ERR(gpio_class);
	}

	device_create(gpio_class, NULL, MKDEV(major, 0), NULL,
				  DRV_FILE); /* /dev/irda */
	return 0;
}

/* 有入口函数就应该有出口函数：卸载驱动程序时，就会去调用这个出口函数
 */
static int gpio_drv_remove(struct platform_device *pdev)
{
	int i;
	printk("%s %s line %d\n", DRV_FILE, __FUNCTION__, __LINE__);
	if (gpios)
	{
		for (i = 0; i < count; i++)
		{
			free_irq(gpios[i].irq, &gpios[i]);
			gpio_free(gpios[0].gpio);
			del_timer(&gpios[i].timer);
		}
		kfree(gpios); // 释放通过 kmalloc 分配的内存
	}
	device_destroy(gpio_class, MKDEV(major, 0));
	class_destroy(gpio_class);
	unregister_chrdev(major, CHR_DEV_NAME);
	return 0;
}

static const struct of_device_id gpio_dt_ids[] = {
	{
		.compatible = "100ask,gpiodemo",
	},
	{/* sentinel */}};

static struct platform_driver gpio_platform_driver = {
	.driver = {
		.name = "100ask_gpio_plat_drv",
		.of_match_table = gpio_dt_ids,
	},
	.probe = gpio_drv_probe,
	.remove = gpio_drv_remove,
};

static int __init gpio_drv_init(void)
{
	/* 注册platform_driver */
	return platform_driver_register(&gpio_platform_driver);
}

static void __exit gpio_drv_exit(void)
{
	/* 反注册platform_driver */
	platform_driver_unregister(&gpio_platform_driver);
}

/* 7. 其他完善：提供设备信息，自动创建设备节点                                     */

module_init(gpio_drv_init);
module_exit(gpio_drv_exit);

MODULE_LICENSE("GPL");
